1. Field of the Invention
This invention generally relates to plastic containers for fluids, and, more specifically, to a plastic blow-molded bottle for storing and shipping chemicals, that can be used for safely storing and shipping both hazardous and non-hazardous chemicals and satisfy industry and government guidelines.
2. Description of the Prior Art
Many containers exist that are footed, e.g., any freestanding two-liter plastic beverage container. However, in most prior art plastic bottles the feature of expansion under pressure can create problems. This is because uneven expansion, especially expansion in the base, can produce xe2x80x9crockersxe2x80x9d (bottles that balloon at their bases under pressure, losing stability and sometimes tending to rock from the upright position). Containers have, therefore, been designed to avoid expansion in or around the feet by thickening or otherwise strengthening the material in the base and feet.
However, it should be noted that the base and legs of all vessels will expand under pressure to some extent. Some designs try to minimize this, and others try to utilize or account for it in ways that avoid xe2x80x9crockers.xe2x80x9d
By far the majority of the blow-molded liquid containers use polyethylene terephthalate (PET) type of polyester as the material for the container. High density polyethylene (HDPE) is rarely used for beverage containers.
Fluting in the neck region of some bottles can be found in U.S. Pat. Nos. 5,217,128 to Stenger, with reinforcing projections.; 5,762,221 to Tobias, with grooves on the dome portion; and U.S. Pat. Nos. 5,988,417, D412,441, D414,441 and D425,424, all of which are to Cheng et al., which all have sinuous groves on the dome portion of the bottle.
Prior art that deals with the expansion of the base and feet include U.S. Pat. No. 6,085,924 to Henderson, where the expansion of the entire foot is allowed; U.S. Pat. No. 6,276,546 to Davis et al. (which includes Henderson, above, and Lynn, below); U.S. Pat. No. 4,978,015 to Walker, where the bottom dome expands; U.S. Pat. No. 3,871,541 to Adomaitis, where side ridges expand; U.S. Pat. No. 5,740,934 to Brady, where the side panels expand; U.S. Pat. No. 5,603,423 to Lynn et al., where the center on the bottom expands; and U.S. Pat. No. 5,906,286 to Matsuno et al., where the center dome on the bottom deforms.
The prior art patents appear to fall into three general categories. The first are bottles or containers that are provided with some rib-like structures in the neck regions, but have a generally flat base (as in the following patents: Dygert, Balz ""285, Balz ""496, Tobias et al., Stenger, and Douglas). The second are bottles that are provided with a footed base structure that may provide for expansion and some profited structure at the upper end of the bottle. However, in most cases the profiled structures are not in the nature of reinforcing ribs but appear, for the most part, to be primarily ornamental. In addition, there appears to be no relationship between the positions of the xe2x80x9cribsxe2x80x9d and the mold or seal lines of the bottle. These patents include: Chang et al. ""441, Chang et al. ""693, Chang et al. ""424, Deemer et al., Chang et al. ""417, Slat, Brady and Adomaitis. The third category include bottles that incorporate legs or feet that may provide for expansion but provide no ribs to reinforce the neck portionxe2x80x9dxe2x80x94these patents include: Matsuno et al., Lynn et al., Walker, Slat ""236, Young et al., Zhang, Henderson and Davis et al.
While numerous blow-molded, freestanding containers have, therefore, been proposed, the chemical industry has, up to now, had a problem in safely shipping liquid chemicals and hazardous materials. Because of the danger of breakage or damage to such bottles or containers, the industry has had to rely on essentially two different types of bottles. Thus, some bottles have been designed primarily to satisfy load drop-tests and others to satisfy internal pressure ratings. Drop tests, in this connection, test the ability of the bottle to withstand impact forces when the bottle is dropped on its mouth or neck portion. Because the mouth and/or neck portions are generally dimensionally the smallest parts of the bottle, any impact forces applied to those regions create maximum stresses in the walls of the container that tend to cause the container to burst or rupture at the weakest areas, typically the mold seams. Existing bottles used by the chemical industry have not satisfied both requirements or specifications established by the various government authorities and transportation laws. The industry""s reliance on two different types of bottles has required that these different types of bottles be separately manufactured, purchased and inventoriedxe2x80x94all this at additional costs. In addition to the extended overheads that result from this, this reliance has at times also presented problems of supply of one type of bottle or the other to the customer base.
Accordingly, it is an object of the invention to provide a universal plastic bottle that can be used both to withstand required internal pressures as well as to withstand impact forces applied to the upper mouth-forming portion or neck of the bottle without damaging the bottle, thereby making it particularly suitable for storage and transportation of chemicals and hazardous materials.
It is another object of the invention to provide a plastic bottle of the type aforementioned which can be easily molded and is inexpensive to manufacture.
It is still another object of the invention to provide a plastic bottle of the type under discussion that can be made from high-density polyethylene and other, similar suitable materials for storing and shipping chemicals, including hazardous materials.
It is yet another object of the invention to provide a plastic bottle as in the previous objects that is freestanding and remains freestanding under a wide range of internal pressures.
It is a further object of the invention to provide a plastic bottle that can be molded with a handle that extends from the neck to a domed portion of the bottle for facilitating the handling of the bottle.
In order to achieve the above objects, as well as others which will become apparent hereinafter, a plastic bottle in accordance with the present invention includes a cylindrical sidewall having a predetermined thickness. A upper mouth-forming portion joins a neck extending therefrom, and a dome-shaped portion is provided between said neck and one axial end of said cylindrical sidewall. A lower bottom-forming base extends from the other axial end of said cylindrical sidewall, all of these being arranged about a central axis of the bottle. At least two substantially vertical, exterior ribs are substantially uniformly angularly spaced from each other about said axis on said neck, said ribs having maximum cross-sectional radial dimensions along said axis generally greater than said predetermined thickness, said ribs reinforcing said neck and distributing forces resulting from the impact of a localized force to said mouth-forming portion towards said dome-shaped portion and said cylindrical sidewall.